package 蓝桥真题.javab组省赛历年真题.填空题;

public class 阶乘 {
       public static void main(String[] args) {
    	      long res=1,MOD=1000000000;
    	      long sum=0;
		      for(long i=1;i<=202320232;i++){
		    	  res=res*(i%MOD)%MOD;
		    	  sum=(sum+res)%MOD;
		      }
		      System.out.print(sum);
	   }
}
